Thursday, October 28, 2010

Saving Sea Turtles With a Lights-Out Policy in Florida

Hatchlings that successfully make the trek from their nests to the relative safety of the gulf and ocean waters find sanctuary from predators in large, floating beds of sargassum seaweed far offshore.

Following sexual maturity 20 to 50 years later, natal hominga behavior of returning to where one was born, and in a turtle's case, employing an instinctual ability to navigate using the Earth's magnetic fieldleads the females back to the beaches where they hatched to make their own nests. Though, if their natal beaches are brightly lit, the females may avoid nesting there.

If a suitable nesting site cannot be found nearby, female turtles may expend valuable energy looking for one, potentially leading to a decrease in the number of nests she is able to lay [fill] that season, Leonard said. Each nest may contain 100 eggs, the size of Ping-Pong balls.

It takes approximately two months for sea turtle eggs to incubate and hatch, a range of 43 to 75 days.

On average, females nest every other year. Some turtle species may nest more than six times in a single season, usually on the same stretch of beach. Because the females can mate with several males and store the sperm, hatchlings have multiple fathers, thus maximizing the population's genetic diversity.

Early Efforts and Missteps

While the importance of providing a safe habitat for the nesting females and their hatchlings was recognized long ago, early protection efforts depended upon voluntary enforcement and were ineffective. Creation of artificial hatcheries and placing restraining cages over nests proved counter-productive.

"It was very frustrating because many of these measures were harming, not helping the turtles," Leonard said.

That's when preserving the night became a priority.

"Instead of trying to make the turtles adapt, we realized that we had to change our attitudes and behaviors," she explained.

Adopted in 1997, the county's Sea Turtle Protection Ordinance involves public education, enforcement of lighting regulations and required review of all new structures and street lighting.

"Prior to adoption of the county ordinance, there were public education efforts aimed at creating a voluntary compliance with keeping artificial lighting off of the beaches. But, they were not very successful and the number of adult and hatchling disorientations was alarming," said Jerris Foote, program manager for Sea Turtle Conservation and Research at Mote Marine Laboratory in Sarasota. "We've seen tremendous results since the county started the program to keep beaches dark," said Foote.

Improvement came one darkened light bulb at a time. Although disorientations still occur, Leonard's goal is to once again see the beaches become a haven for female sea turtles and their hatchlings.

For the past four years, the Sarasota County scientist has systematically worked with the owners of the more than 700 coastal properties, educating them in how to safely darken their beaches.

Photographic surveys taken over the years prove that the beaches are getting darker and safer for the sea turtles. Numerous other communities in Florida have adopted or are considering sea turtle protection ordinances.

"I believe we are successfully changing the mindset of the coastal residents," Leonard said. "That's good for future generations of sea turtles and for future generations of humans who will be able to enjoy having these creatures on their beaches."